1. Field of the Invention
The present invention pertains to integral skin rigid polyurethane structural foam compositions. More particularly, the present invention relates to the preparation of integral skin rigid polyurethane structural foam which contains polyether polyol prepared by ethoxylating triisopropanolamine, an organic polyisocyanate, a blowing agent, catalyst, and optionally a chain extender.
2. Description of Prior Art
The use of triisopropanolamine (TIPA) in combination with alkylene oxide adducts of aliphatic and aromatic amines has been disclosed in the prior art. U.S. Pat. No. 4,588,803 teaches the preparation of low shrinkage polyurethane sealant compositions employing, among other reactants, ethylene oxide adducts of toluenediamine and triisopropanolamine. U.S. Pat. No. 4,605,725 teaches the preparation of polyurethane sealant compositions employing alkylene oxide adducts of monoethanolamine blended with triisopropanolamine. U.S. Pat. No. 4,780,482 teaches the use of TIPA as a chain extender in rigid integral skin polyurethane foams to impart flame retardancy. The inventor has now found that TIPA used as an initiator in the preparation of polyether polyols also imparts good flame retardancy.